Research of Pre-peak Deformation Detection of Rock with Fiber Bragg Grating Sensing

In order to obtain more precise test data of deformation and damage of rock, the paper proposed a method which uses fiber bragg grating sensing technology to detect deformation and damage process of rock. The method makes fiber bragg grating paste on axial direction of rock sample and makes single cycle load experiment at 815MTS hydraulic servo-machine for the rock sample, which is used to detect axial displacement of pre-peak deformation stage of rock. The experiment is stopped when the rock sample is damaged. The experiment result showed that strain value of fiber bragg grating sensing technology converted by transfer coefficient has good consistency with strain value of MTS, and relative error rate is only 3.2%, so using fiber bragg grating sensing technology can realize high-precision test of pre-peak deformation of rock.